1. The cross-section of bamboo

 When you cut the bamboo by the saw and separate it last, I think it's very difficult to cut the skin of the surface of the bamboo.

 My father cut the bamboo going around completely, although the saw is sawn while turning bamboo, and cut the surface beautifully without coming off.
 Therefore, the site of the saw edge has been left purposely, as shown in the section of the single-flower vase. Without processing the artificial purposely, leaving the cutting edge as it were, his work has his own valuables. 

 For example, I heard that the basic original tea ceremony had been held in the battlefield using the materials as it were in the nature. This is the real Samurai's mind.
Single-flower base 

Director Hideaki Kosuge  Postmaster@i-OfficeK.com